When to pot JBP seedlings

[ADO]

Hi,

My current batch of JBP seedlings are about 5 weeks old. they are starting to get their true leaves. At what point at their early life should I put them in the next size up pot. At the moment they are either in seed trays or in 50 mm seedling tubes.
they are all in a fairly sterile mix so I am feeding them.

cheers

Adrian

[mtarros]

Hi,

It all depends on what you want to do with them if you want to make seedling cuttings and the stems have changed to a purple colour then you can do, but it might be getting to hot to do that now??

The ones in the 50mm seedling tubes will be ok for about one year, i had my JBP in them for around that time, then i put them into 3 inch round pots.
of course you can put them into larger pots to try and speed them up a bit more.

The ones in the seed trays will be ok for some time but you may lose some due to lack of sun.

I cant remember when i moved them out of the seed trays and put them into the 50mm tubs i think it was around 2 months.

[Rolf]

Hi Adrian,

I personally would wait another 5 weeks or so to have a reasonable root system to work with. Then you can start wiring them as well if you like!!

I let mine grow at least for 3 month then work on the root system (cut off the tap root) spread the roots nicely and repott in free draining soil or mixture of small akadama and pumice.

I also start shaping them because you can't start early enough with black pines. It is getting harder later on.

seedling_1.jpg

seedling_2.jpg

pine_mature1.jpg

mature_pine.jpg

Thats my

Cheers

Rolf

[Mojo Moyogi]

Rolf saying that is is underselling it a bit , thanks for posting some nice little JBPs.

Cheers,
Mojo

[ADO]

Hi Adrian,

I personally would wait another 5 weeks or so to have a reasonable root system to work with. Then you can start wiring them as well if you like!!

I let mine grow at least for 3 month then work on the root system (cut off the tap root) spread the roots nicely and repott in free draining soil or mixture of small akadama and pumice.

I also start shaping them because you can't start early enough with black pines. It is getting harder later on.

seedling_1.jpg

seedling_2.jpg

pine_mature1.jpg

mature_pine.jpg

Thats my

Cheers

Rolf

Hey Rolf, thanks for that. some awesome pines you have there. the seedlings at this stage have quite thin stems. with a bit of feeding etc I can hopefully pot them up in the time period you specified. cheers

Adrian

[shibui]

JBP seedlings can be potted at any time. I start to prick them out even before the first true leaves. At that stage they often just have a single root going down which I cut quite short then pot into a 10 cm pot. The cut root will very quickly put out more lateral roots where it has been cut. These laterals will be a great start to a lateral root system for your future tree.
If you prick them out a few weeks later the roots will have started to produce some lateral roots. At that stage I just shorten the main root to where there is the best cluster of lateral roots to encourage those and discourage downward ones.
I have also potted up seedlings at a couple of months old. Usually there are some with few lateral roots but, again, prune any downward roots at the best cluster of laterals, even if it is just a few really fine ones, and the tree will respond by growing more, better lateral roots.
I have often left seedlings in the community pot for a year and occasionally 2 years before potting up into individual pots. They do not develop much when crowded together but will take off when given some space.

In my experience, there is not much difference in the final product but early root pruning does give better lateral roots that will make better nebari.

I agree with Rolf's advice to start shaping early. I'd also add that regular pruning will give low branching and avoid tall straggly trunks. I have put a couple of posts on growing JBP seedlings on the Shibu Bonsai Blog.http://shibuibonsai.com.au/black-pine-seedlings/ There's a couple of other posts there you might find interesting too.